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TT: Fachverband Tiefe Temperaturen
TT 28: Transport - Poster Session
TT 28.36: Poster
Thursday, March 29, 2007, 14:00–17:45, Poster A
Charge and spin transport in double quantum dot systems — •Georg Begemann, Ralph Peter Hornberger, Andrea Donarini, and Milena Grifoni — Universität Regensburg, Theoretische Physik
We consider spin and charge transport through two quantum dots in series, described by an extended Hubbard Hamiltonian. This model Hamiltonian describes conjugated molecules as well. Unpolarized as well as spin-polarized leads are considered. We calculate physical quantities like the conductance or the average spin using two different approaches.
On one side we start from a Liouville equation approach for the system density matrix and calculate I-V-Vg characteristics perturbatively in the tunneling.
On the other hand we evaluate the Green’s functions of the interacting systems using the equation of motion technique, which allows a nonperturbative treatment of the coupling. To this extent we generalize the approximation by Meir, Wingreen and Lee [1] for the single-site to the two-site case.
[1] Y. Meir, N. S. Wingreen and P. A. Lee: Transport through a Strongly Interacting Electron System: Theory of Periodic Conductance Oscillations, Phys. Rev. Lett. 66, 3048 (1991)